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Elusive Drive-line Vibration Issue

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Fuel starved/engine struggling under load

48re three accumulator springs?

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You can isolate the transmission and the clutch from the equation by pressing the clutch in while the vibration is occurring at road speeds.
If the vibration changes with the speed of the engine then its obviously related to the engine, either clutch assembly, internal issue, or harmonic balancer.
If the vibration remains while the clutch is in then continue to hold the clutch pedal in and shift into neutral. If the vibration still remains then its likely related to the driveline as the only component spinning at the same rate as the driveshaft at that point inside the transmission is the counter shaft. That would mean inspecting more closely all the joint locations. A u-joint can still feel tight but have a dry or tight cap which will result in changes in the oscillation pattern and cause vibrations. Or the driveline lost a weight or fell out of balance by changing joints or bent tubing or yoke ears. :)

I tried to duplicate this morning.. as it is intermittent in nature and only occurs from ~ 60 --> 50mph during decel with the exhaust brake, it is difficult to check all the above cases at once. The results are as follows; Severe vibration occurs, clutch pedal in, (engine speed reduces) small improvement in vibration but vibration remains ( likely due to the load of the exhaust brake removed ). I sped up and tried again this time trans in neutral, vibration basically gone. I did not try clutch in / trans in neutral, and I have not had the chance to try since I ran out of strait roads this am. I will try again this evening on the way home. Per your last post, this vibration is in between a foot massager and a loose wheel, but I attribute that to the fact that in 6th (when it occurs) the engine speed is fairly low, It does not seem to be there in 5th although I have felt "something" in the past, just with the engine wound up and all the "other" music and vibration from the mighty engine it is tough to ferret out.

thoughts?
 
I tried to duplicate this morning.. as it is intermittent in nature and only occurs from ~ 60 --> 50mph during decel with the exhaust brake, it is difficult to check all the above cases at once. The results are as follows; Severe vibration occurs, clutch pedal in, (engine speed reduces) small improvement in vibration but vibration remains ( likely due to the load of the exhaust brake removed ). I sped up and tried again this time trans in neutral, vibration basically gone. I did not try clutch in / trans in neutral, and I have not had the chance to try since I ran out of strait roads this am. I will try again this evening on the way home. Per your last post, this vibration is in between a foot massager and a loose wheel, but I attribute that to the fact that in 6th (when it occurs) the engine speed is fairly low, It does not seem to be there in 5th although I have felt "something" in the past, just with the engine wound up and all the "other" music and vibration from the mighty engine it is tough to ferret out.

thoughts?

So based on what you said, let me clarify in order to make sure I understood you correctly.....

First attempt - Driving along you simply pressed in the clutch while leaving it in gear. Still coasting along, the engine RPM's dropped down and the overall vibration was reduced but still there.
Second attempt - Driving along you shifted into neutral and let the clutch back out. Still coasting along, the engine RPM's dropped down and the vibration was basically gone.

This would elude to the problem being within the input shaft side. Possibly a bearing going bad on the input shaft or the clutch disc itself. Because even when the clutch is in the counter shaft (the output shaft) is always spinning at driveshaft speeds as its directly connected. And even though the input shaft is receiving no power from the clutch when you have the clutch pedal in, the input shaft will continue to spin with the counter shaft because the transmission is still in gear.

So that said, by you then putting it in neutral and the vibration going away indicates that the input shaft is no longer spinning at the same rate as the counter shaft since its no longer in gear, but now spinning along with the engine. So again, if the vibration goes away with the transmission in neutral and the clutch out then its related to either an input shaft bearing or the clutch disc.

BUT.....in case it hasnt already been throw out there in this thread, I'd advise removing the front driveshaft and taking it for a drive just to confirm before pulling the transmission back. Because ya never want to fully trust an internet diagnosis. #ad


Hope I didnt just make that overly confusing..... #ad
 
Nope, I'm there with ya... I've been putting this off hoping it is something else. Guess I'm going in, I'll wait till after Christmas. And yes I pulled the front shaft weeks ago and it didn't seem to be any better but I'll do it again to confirm. Hey it has to come out anyway right:-laf I really just hope it's the clutch disk or pilot bearing.
 
Check to see if there are a lot of weights * on one side of the tire.
When I have seen this the tire is bad.
If you a tire weighted down on one side you can jack the truck so both sides are even. Use some thing with a straight side (box, tool box...) *put close to the rear (back) *tire and spin watch tire see how much of gap between tire and box. On front tires put the box in ftont of tire and spin. *A roving tire man showed me this trck many years ago.
 
Well I hope its something simple, but do post back with what you find out. :)

OKAY..... I know this is a nail biter.. UPDATE.

I pulled everything finally last night and to my surprise I have no pilot bearing.. only the remnants of a long departed one! No remaining race, needles, anything. Input shaft is decently torn up, not too loose, but definately not reusable without some machining or replacement. Now I am trying to figure out what to do. Anyone replaced a input shaft before, seems strait forward in the manual, and looks like "special tools" don't really come into play unless you are replacing / removing speed gears. I have access to lift, hoist, machine shop tools, and measurement equipment, Looks like probably I need (obviously a new clutch) and input shaft and best case input shaft main bearing / seal. Going to take a look again today, but I am deeply considering taking a stab at it since all the gears look to be in excellent shape.
 
What a bummer but at least you found it. And.....hey, we kinda pin pointed it too so at least you weren't spending money replacing good parts.

As for the pilot and the input shaft..... You obviously have to do whats financially appropriate for you but what I would do is inspect the clutch while you're that far in there and possibly just replace everything, depending on how many miles are on them. Meaning, you can replace it with an OEM clutch or this is an opportunity to upgrade to a quality clutch kit which will not only hold more power but should come with better than OEM parts. And if the pilot is completely toast then it allowed the input shaft to float around which places more wear and tear on the clutch disc hub and pressure plate and input shaft bearing.

For example of quality, the OEM pilot bearing you "had" was an exposed needle bearing design but the pilot bearing from Southbend is an oversized sealed roller bearing with a flywheel thats machined to accept this big bearing. They'll also have a replacemment input shaft for you too.

Below is a picture of what the SB pilot looks like. :)

#ad
 
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Yes I "planned" to replace everything..... But I am having a hard time swallowing sendin a perfectly good trans to a rebuilder to replace the input shaft. A 10cent needle bearing failure could cost me 3k for a rebuild an then I still have to buy a clutch...... Deeply considering cutting my losses.

Has as anyone replaced a 5600 input shaft themselves?
 
Absolutely. Replacing the input shaft does not require a transmission shop. If I remember correctly they cost around $300 (ish). You may have to have the new bearing pressed though.....
 
The 5600 input shaft does not install through the front like a 4500, requires a full tear down to access. Yes the parts are not to bad $$ just getting to them. Question, since the bearings feel good and gears look good, can I replace the clutch with the south bend and run the input shaft as is since the bearing is not a roller(no contact) and the race would hopefully be riding on the un damaged part of the input shaft? I miked the shaft this am and it is worn about 1/2 a mm in the center.. so the ends of the nose (around)10mm is still 19mm and the center necks down to a little over 18.5mm at the worst, I hate to tear it all down if I can make it run with a sealed ball brg. As I said trans was driving just fine with no brg at all.... just a little vib on decel
 
My apologies..... I forgot we were talking about the 5600.

Yes, unfortunately the transmission will have to be disassembled which isnt fun and isnt something the every day DIY guy is capable of. Thats not to say you cant either.

As for the input shaft and running it, well that would depend on its condition and how well it fit whatever bearing or bushing you can get to fit/work. Can you post a picture of what it looks like?

That said, if there's ANY slack in the fitment of the input shaft and the pilot then it will simply repeat the episode over again until it beats the pilot bearing to the point of bad vibrations.
 
Well I've decided I like the truck too much to bandaid it so I'm going in, I think I can swap in a new shaft and brgs, it won't be a cake walk but it's doable. I'll post some pics soon, thanks again TDR! Cheers
 
Well, tore it down last night, rev synchro is completely toast, I assume 1st and maybe 2cnd will be the same since they were doing all the work to stop those big shafts and "no pilot bearing drag". I am thinking main shaft and counter shaft bearings, they feel good but races are cloudy, and the mainshaft big ball bearing is rough... ( Mainshaft nut was loose) and then 3 synchros and seals ( 5th gear synshro looks great! That being said I usually use Quad4x4 because they carry timken bearings ( same as OE) for axles etc, but they do not have anymore shim kits, ( I assume I will need to re-shim with new bearings to achieve the correct shaft end-play, Does anyone here have a TM parts house they recommend? I will likely still get the bearings and shaft from Quad, but any other small parts I may have to look elsewhere ( ugh... I hope not cheap Chinese parts!)
 
Unfortunately hecho en China is going to be a problem..... Even Quad4x4 will tell you that most or all of the parts you get from them will be from overseas. My suggestion is check everywhere. I've heard some good things about http://www.blumenthalmfg.com/

I've heard some bad things lately about Standard Transmission too so take that with a grain of salt. I would certainly ask in another thread and/or in other forums where anyone is getting or has gotten their rebuilt 5600. Because so many parts are inferior Chinese garbage, getting quality is a problem.
 
Also, I believe Timken is not American manufactured anymore either. I understand the only bearing manufacture that still resides within the states is SKF.
 
yeah, I called both Std and Blumenthal, I feel like they are good people, and deliver a good product,( i have heard the opposite, but like are trucks if one brand was better that the others, the others would be out of business). With shipping (500$) and tear down ($500) at either place, I'm in it $1k before I get to the problem ( I can buy the parts alone for that). I will call them and ask but I suspect they are in the bushiness of selling transmissions not parts. They said they would fix what I wanted with no warranty or propose a repair plan... I digress they are in the business of selling transmissions so I assume my rebuild plan with "necessary parts" would be darn close to the exchange $3100 for a reman. I will look around though because Master rebuild kits for these things are all over the board cost cost! I have her all torn down now, and I am going out tonight to pull the 1/2 sychros just to confirm how many I actually need. ( example Quad sells synchros for $50 each) Other web sellers are selling synchro kits for $200 for all 7 (including brass and steel blocking rings) and the shims, and shift rail guides... who is charging the premium if they are all truly overseas sourced?
 
Also I am taking lots of pictures so hopefully if I can find the time afterward, I can put together something helpful and meaning full for the next guy
 
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